(1) Field of the Invention
The invention relates to photostatic film and more particularly to reclaiming the film so that it may be reused.
(2) Description of the Prior Art
As used herein, the term "photostatic film" is used to include all film made of a material, such as Mylar or a similar plastic, having a coating on one or more sides of a material, such as zinc oxide, which because of its light sensitive and electrostatic properties can be used in the process of lithographic or offset printing.
The term "bunny brush" refers to a type of brush having extremely soft bristles. This brush is familiar to those having ordinary skill in the art of printing or photocopying. The composition of the brush is particularly described in CLARKE's U.S. Pat. No. 3,615,813 at columns 3 and 4.
In the process of printing first a master copy is prepared. Then the master is transferred to photostatic film, said film photostatically attracting particles, usually carbon, in the pattern of the material. This film is then used to prepare the printing plate from which copies are printed. After the film is used once it is discarded. The film is very thin and any attempt to reclaim it which creases said film would render it unusable.
Specifically, photostatic film is used in printing newspapers. A master is prepared. Then, the master or the "layout" of the page is photostatically transferred to a long, wide web of photostatic film. Pyrofax Transfilm, a product of the Printing Products Division of 3M Company of Minnesota, is an example of such a photostatic film. One common form of this film is a web 19" (47.5 cm) wide and 900 feet (274.3 meters) long, which is wound upon a cardboard core. The cardboard core is a hollow cylinder with an internal diameter of about 3" (7.5 cm). Then, the image upon the photostatic film is transferred to printing plates for printing the copies of the newspaper. After the image has been transferred from the photostatic film to the printing plates, the used film is rolled upon a used core. In present commercial practice before this invention, the used film was then discarded.